PEROMEDUSAE. 



165 



Sub-order 2. PEROMEDUSAE. 



With 4 interradial rhopalia (with otoliths and eyes) ; with 4 perradial tentacles, 

 or with 12 tentacles (4 per- and 8 adradial, Fig. 135); with 8 or IG-T^arginal 

 lobes. The 4 radial gastral pouches are separated from one another by very 

 short septal-unions or septa, so that the 

 stomach may be said to be surrounded by 

 a wide circular sinus, communicating with 

 it by 4 ostia (Fig. 99). The circular sinus 

 gives off towards the periphery of the 

 umbrella 8 or 16 flat pockets, each of 

 which gives off two lobe -pockets, and 

 between these one pocket to a tentacle 

 or sense - body. 4 horse - shoe shaped 

 gonads in the ventral wall of the circular 

 sinus. 



FIG. 135. Periphylla hyacinthina (after Haeckel). FIG. 136. Charybdea marmpialis, natural 



Rf annular groove dividing the umbrella into size. T tentacles ; Ilk marginal bodies 5 



a proximal conical part, and a ventral lobed Ov gonads. 

 region. 



Fam. 3. Pericolpidae. With 4 perradial tentacles, 4 interradial rhopalia, 

 and 8 adradial marginal lobes. Pericolpa H. ; 'Pericrypta H. 



Fam. 4. Periphyllidae. 12 tentacles, 4 rhopalia, 16 marginal lobes. 



Peripalma H.; Periphylla H. (Fig. 135). 



